Nobel laureate and former Fermilab director Leon Lederman dies at 96

He was a leading light of particle physics, directing one of the most prestigious physics laboratories in the world. He won the Nobel Prize and irked his physics colleagues by coining the term “the god particle” to describe the Higgs boson. That long, rich life ended early Wednesday morning when physicist Leon Lederman died of complications from dementia at the age of 96.

Lederman first made his mark as a young physicist working at Columbia University’s spanking-new cyclotron in the 1950s. In June 1956, two theoretical physicists, Chen Ning Yang and Tsung-Dao Lee, published a paper proposing that parity might not be conserved in weak interactions, suggesting several experiments to test their hypothesis. Parity had been considered a fundamental symmetry in physics, holding that our world is indistinguishable from its mirror image. In other words, there should be no difference, at the subatomic scale, between left- and right-handed rotations, or opposite sides of a subatomic particle.

Between Christmas and New Year’s, a team of physicists at the National Bureau of Standards led by Chien-Shiung Wu performed a series of experiments. Wu and her colleagues were startled to find that—at least when it came to the beta decay of cobalt-60 nuclei—parity was indeed violated: nature appeared to be slightly left-handed. Lederman was lunching at a Chinese restaurant near Columbia with coworkers when he heard about the results. He quickly verified them by performing his own different set of experiments and came to the same conclusion.